Insecticide



Patented .iuiy W42 INSECTICIDE Lloyd E. Smith, Washington, 1). 0., assignor to Henry A. Wallace, Secretary of Agriculture of the United States of America'andh-is successors No Drawing. Application May 6, 1938,

Serial No. 206,387

(Granted under the act-of March 3, 1883, as

amended April 30, 1928; 370 0. G. 757) 2 Claims.

This application is made under the act of March 3, 1883, as amended by the act of April 30, 1928,

' and domestic animals when taken by. mouth and which can be used in place of lead arsenate and other arsenicals for destroying insects without leaving a harmful residue on fruits and vegetables.

I have found that the class of organic compounds known as xanthenes and derivatives thereof are eflective in killing many species of insects whether applied externally or internally; that these organic compounds may be sprayed or dusted upon delicate vegetation without inluring it; that these materials are even more ef- Iective than lead arsenate .and other commonly used insecticides and that they are relatively nontoxic to warm-blooded animals. This class of compounds may be represented by the general formula in which R and R' are benzene nuclei in each of which 2 adjacent carbon atoms take part in forming a six membered ring.

- Some of the hydrogen atoms normally attached to R and R may be substituted or replaced by alkyl, cycloalkyl, aryl, heterocyclic nuclei, or halogen, nitro, amino, hydroxy, alkoxy or aryloxy groups.

These products may be reduced to impalpable power by grinding and applied to vegetation either dry as adust or wet as a. spray. The products being soluble in refined mineral oils, may be applied as a component of an oil emulsion spray. When applied as a spray inwater it is desirable to incorporate an efiective wetting agent such as one of the so-called sulphonated oils. These products may also be applied by dissolving them in acetone and pouring the acetone into water whereupon a fine colloidal precipitate is formed. This may be applied directly to plants or may be combined with a suitable wettingcagent and then sprayed.

As an example of the toxicity of this class of compounds it was iound that One part to 1001000 parts of water gave a 96% kill of mosquito larvae.

Having thus described my invention what I claim for Letters Patent is:

1. As insecticide containing as its essential active ingredient one of the class of compounds known as. xanthenes.

2. An insecticide containing as its essential active ingredient xanthene. 

